polywell plasma confinement

[ahura999]

Hi all , thought i'd start a thread and see where it goes , i have been building geodesic or polyhedral structures and exploring the polywell/farnsworth/gray concepts .

The polywell is a plasma confinement concept that combines elements of inertial electrostatic confinement and magnetic confinement fusion, intended ultimately to produce fusion power. The name polywell is a portmanteau of "polyhedron" and "potential well." The experimental fusors that employ this concept are called "Wiffle Balls".

The polywell consists of electromagnet coils arranged in a polyhedral configuration and positively charged to between several 10s and low 100s of kilovolts. This charged magnetic polyhedron is called a MaGrid. Electrons are introduced outside the "quasi-spherical" MaGrid and are accelerated into the MaGrid due to the electric field. Within the MaGrid, magnetic fields confine most of the electrons and those that escape are retained by the electric field. This configuration traps the electrons in the middle of the device focusing them near the center which produces a virtual cathode (negative electric potential). The virtual cathode is used to accelerate and confine the ions to be fused which, except for minimal losses, never reach the physical structure of the MaGrid. It was developed by Robert Bussard under a US Navy research contract as an improvement of the Farnsworth-Hirsch fusor.


Polywell - Wikipedia, the free encyclopedia

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ahura

[ahura999]

Inertial electrostatic confinement

from wiki a little more reading

Inertial electrostatic confinement - Wikipedia, the free encyclopedia


The best-known IEC device is the Farnsworth-Hirsch Fusor.[1] This system consists largely of two concentric spherical electrical grids inside a vacuum chamber into which a small amount of fusion fuel is introduced. Voltage across the grids causes the fuel to ionize around them, and positively charged ions are accelerated towards the center of the chamber. Those ions may collide and fuse with ions coming from the other direction, may scatter without fusing, or may pass directly through. In the latter two cases, the ions will tend to be stopped by the electric field and re-accelerated toward the center. Fusors can also use ion guns rather than electric grids.

The fusor's popularity is largely because simple versions can be built for as little as $500 to $4000 (in 2003 US dollars), making it accessible to hobbyists, science fair contestants and small universities. Even these simple devices can reproducibly and convincingly produce fusion reactions, but no fusor has ever come close to producing a significant amount of fusion power. They can be dangerous if proper care is not taken because they require high voltages and can produce harmful radiation (neutrons, gamma rays and x-rays). The basic IEC device has been developed as a commercial neutron generator for industrial applications: first with the trade name FusionStar and now NSD-Fusion.

Two newer approaches both try to solve a problem found in the fusor, which is that some ions collide with the grids. This heats the grids, sprays high-mass ions into the reaction chamber, pollutes the plasma, and cools the fuel. The Polywell uses a magnetic field to trap a quantity of electrons, fuel ions are then accelerated directly into the middle where they are trapped by the electron cloud that forms a "virtual electrode". Another modern approach uses a Penning trap to trap electrons in a system otherwise similar to the Polywell.[2][3]


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